Tests and diagnosis

By Mayo Clinic Staff

Your doctor will review your medical history and conduct a comprehensive eye examination.

Your doctor may perform several tests to diagnose glaucoma, including:

  • Measuring intraocular pressure. Tonometry is a simple, painless procedure that measures your internal eye pressure (intraocular pressure), after numbing your eyes with drops. It's usually the initial screening test for glaucoma.
  • Test for optic nerve damage. To check for damage in your optic nerve, your eye doctor uses instruments to look directly through the pupil to the back of your eye. This can reveal slight changes that may indicate the beginnings of glaucoma.
  • Visual field test. To check whether your visual field has been affected by glaucoma, your doctor uses a special test to evaluate your side (peripheral) vision.
  • Visual acuity. Your doctor will test your ability to see from a distance.
  • Measuring cornea thickness (pachymetry). Your eyes are numbed for this test, which determines the thickness of each cornea, an important factor in diagnosing glaucoma. If you have thick corneas, your eye-pressure reading may read higher than normal even though you may not have glaucoma. Similarly, people with thin corneas can have normal pressure readings and still have glaucoma.
  • Other tests. To distinguish between open-angle glaucoma and angle-closure glaucoma, your eye doctor may use a technique called gonioscopy in which a special lens is placed on your eye to inspect the drainage angle. Other tests, such as imaging tests, have been developed and may sometimes be used.
Oct. 02, 2012